Gun



J. C. WHITE April 14, l936 GUN 2 Sheets-Sheet l Filed March 24, 1935 lys 2 Sheets-Sheet 2 Aprr 34, H936. 1 c;- WHlTE GUN File-d March 24, 1933 \W\ Nw v KW .na. f @8 m, m. m w um. Oh f 4 hm, hm; W v y@ 7 1 @1% w. Qkwmpfww r Ww -m\ OA mwN MN QmKMN mm I W W, f Q hy, a d? MM. om @Mm Q T s w? mi. mm &\ wM///V// w Qmu TW@ A y /`7 fi.; l m@ w. v www@ NN v\b\\ Q MU ?atented Apr., it, i936 UNITE STATES PATENT oFFlce GUN Application March Z4, 1933, Serial No. 562,475 In Great Britain April 11, 1932 21 Claims.

My present invention relates to iirearms and more particularly aims to provide an improved recoil-operated breech mechanism for self-loading military and other guns, said breech mechanism providing a high factor of safety and being relatively simple and compact in structure and of light weight.

In the drawings, illustrating, by way of example, one embodiment of my invention,

Fig. 1 is a central longitudinal section through the breech mechanism, showing the parts in their position at the moment of iiring;

Fig. 2 is a view corresponding to Fig. 1, but illustrating the parts in their full open position;

Fig. 3 is a partial side elevation of the receiver and a fixed part secured to the gun stock, the receiver being positioned as at the completion of its short recoil;

Fig. 4 is a view partly in horizontal section and partly in plan, substantially upon the line II- of Fig. 1;

Figs. 5 and 6 are respectively a side elevation and a rear end view, partly broken away, of the breech block;

Fig. 7 is a side elevation of the intermediate member or link;

Figs. 8 and 9 are respectively a side elevation and a rear end view of the crank;

Fig. 10 is a view in perspective of an arm or link operatively connecting. the crank and the actuator;

Fig. 11 is a detail view upon a larger scale showing a portion of the return mechanism seen at the lower right portion of Fig. 2;

Fig. 12 is a horizontal section on the line I2-I 2 of Fig. 1;

Figs. 13 and 14 are vertical sections on the lines I3-I3 and III-I4 respectively of Fig. 12, looking in the direction of the arrows; and

Fig. 15 is a perspective of the stock abutment.

Referring iirst more particularly to Figs. 1 to 4, the gun comprises a barrel I threaded or otherwise iixed at the fore part of a receiver 2, the

rear portion of which is closed by a removable plate 3. The barrel and receiver are slidably associated with the gun stock or frame, a portion of which is indicated at d. abutment 5, seen separately in Fig. 15, isanchored in the stock as by means of the screws illustrated.

The breech mechanism as illustrated is a toggle-joint or crank structure comprising three main elements which are readily assembled or 5 dismounted with respect to the receiver, as a A frame or stock unit. These include a rectilineally guided breech block proper B, an intermediate pivoted a-lement or link 1 and a rear pivoted element or crank 8.

The block 6 is provided with later-ai ribs 9 riding in grooves I0 in the receiver (Figs. 2 and 4) 5 whereby it is guided for reciprocating movement. The block carries a fulcrum pin II removably held in place by a spring pressed pin I2 whose spring I3 bears at its forward end against a plunger I4 engaging the extractor I5, thus servl0 ing as a spring for the latter. The fulcrum pin II of the block is received in a boss I6, Figs. 5 and 6, positioned between the forward ears I1 of the link 1, Fig. 7, the latter being apertured for reception of the ulcrum pin II. l5

The link 1, which houses a portion of the iiring train to be referred to, is pivotally associated, at its rear end, with the fore part of the crank 8, by means of the rear tongue or vboss I8 of the link received between corresponding ears I9 20 of the crank, said boss and ears being apertured for reception of the toggle pin previously mentioned. This pin is removably held in place by the key 2 I, Figs. 1 and. 2, itselfleleasably pinned in position. The crank 8 in turn is pivotally 25 positioned at its rear end in the receiver by the crank fulcrum pin 22, removably held in the receiver walls as by means of a spring element 23, the rear portion of which surrounds and seats in a groove in the fulcrum pin 22 while its fore 30 portion engages and locks in place the screw plug 24, forming a housing for the spring 25 of the buier 26.

In the closed or locked position of the breech mechanism parts, as shown in Fig. 1, the breech block, link and crank form in effect a single piece or unitary mass for closing the breech and transmitting the firing stresses directly to the receiver. Said main parts of the breech closure as a whole, that is, the breech block proper 6, link 1 and 40 crank 8, are so constructed and arranged at their adjoining portions, and in relation to the receiver, that the pivot and fulcrum pins are relieved of the firing strains, the latter being transmitted to the receiver directly by the main elementsithemselves, independently of the pivot and fulcrum pins.

For this purpose abutting locking surfaces of substantial area are formed, concentrically with the fulcrum pin II of the block, between the breech block and the link, as indicated at 21, 21, Figs. 1, 2, 4, 5, and 7. Other large area locking surfaces are likewise provided between the link 1 and the crank 8, as indicated at 28, 28 by the dotted line in Fig. 1 and seen in full line in Figs. 55

' arately in perspective in Fig. 10.

4, 7, and 8, formed respectively at the sides of the link and at the front face of the bosses or ears of the crank, concentrically with the link and crank connecting or toggle pin 26.

The crank itself is further provided with solid and large area pressure-transmitting shoulders 29, formed concentrically with the crank fulcrum pin 22 and adapted to make abutting engagement with similarly formed opposed shoulders 30 on the receiver side walls, in the closed position of the parts; see particularly Figs. 1, 3, 4, 8 and 9. As indicated by the dotted lines at the right in Fig. 4, the crank fulcrum pin 22 has a clearance with respect to the crank Hence, the breech pressure attendant on ring is transmitted directly to the crank and by the latter, through the interengaged large area surfaces 29, 3G to the receiver itself. Accordingly no shearing strains are placed upon the pivot or fulcrum pins, and particularly is the crank fulcrum pin 22 left free of such strains.

To assist in the breech opening effort, there is pivotally connected to the rear portion of the crank 8, at 3i, an actuator link 32, shown sep- This actuator link is in turn pivotally associated, by means of its cross piece 33, with an actuator 34.

The actuator 34 is slidably mounted in the lower rear portion of the receiver 2, the latter being provided with ribs 35, Figs. 13 and 14, received in corresponding grooves or guideways at the sides of the actuator. The actuator in part houses the main counter-recoil or return spring 36, also theinitial or auxiliary return spring 3l, as well as a pair of cushioning and breech opening spring-pressed plungers 38, see particularly Fig. 12. The springs 39 of the latter are removably housed in the actuator, wherein they are held in the screw plugs 40.

The actuator 34 includes a centrally disposed and rearwardly projecting tubular portion 4l, closed suiciently at its rear end to provide a. rear abutment for the main return spring 36, which is received in said tubular portion 4 I. As best seen in the detail Fig. 11, said return spring 3S bears rearwardly against a washer 42, which in turn is received against t-he rear of the tubular portion 4l oi the actuator. Within the main action or return spring 36 is a floating sleeve 43 which assists in guiding the main spring 36 and also houses the auxiliary spring 31. The latter is positioned between a plunger 44, at its rear end, and a stud 45 received in and removably pinned to the sleeve 43 by the bayonet joint connection seen in Fig. 2. Said stud 45 is xed in the adjacent depending portion of the receiver 2, Fig. 12, against which receiver portion the main spring 3S also bears at its fore end. The sleeve 43 has a head 46 at its rear end against which the washer 42 will abut when the action spring is removed from the actuator, thereby keeping the spring from ying cfr from the sleeve 43, and conveniently but removably holding the parts togetrier.

The rearward pressure and reaction thrusts of the action springs and of the actuator and its plungers, as well as any remaining rearward pressure of the receiver itself, are received directly by the frame or stock abutment 5 previously mentioned, which is stationarily but removably anchored in the stock. Said abutment 5 is shown separately in perspective in Fig. 15. It

includes the main forwardly facing, pressurereceiving surface 47, lateral guides 48 for sliding cri-operation with the-actuator, a bore 4S for aosma'r sliding reception of the rearwardly projecting portion 4l of the actuator, and the closed rear wall 50 against which said rearwardly projecting portion of the actuator, and the parts housed therein, are adapted to abut. Said stationary abutment 5 is provided with forwardly facing receiver-stops 5a, engaged by a rear portion of the receiver at the end of its full recoil, which recoil, as hereinafter pointed out, is extremely short, being as herein illustrated but about 1A, inch total. Said rearmost or full-recoil position of the receiver relative to said abutment and the frame or stock is illustrated in Fig. 3. At the upper portion of this stationary abutment 5 are rearwardly facing shoulders 5I constituting forward or return stops for the receiver and its supported parts, at the end of the counterrecoil, said stops being then engaged by the rear plate 3 of the receiver, see Figs. 1 and 2. It will be noted that the length of the total recoil of the receiver, being herein but about 1A; inch, is but a minor fraction of the length of the riile cartridge. As the military cartridge intended for use with the rie as illustrated herein, see Fig. 1, is approximately 31/4 inches long, which is also approximately the length of the Springeld cartridge, the total recoil is but about I/ 13 the length of the cartridge. The total recoil distance of the receiver is readily apparent in Fig. 2, for example, as indicated by the horizontal space between said rearwardly facing shoulders 5l of the abutment 5 and the rear plate 3 of the receiver.

Referring again to Figs. 1 and 2,the bieech block 6 houses a firing pin 52 and also the ejector 53 including its spring 54 and spring housing 55. The link 'I carries the slidable striker 55 which is adapted, at the proper time, to make firing Contact with the firing pin 52. The striker 56 is urged forwardly by the striker spring 51 and is formed with a cooking notch 58 adapted to receive the nose of the sear 59 by which the striker is held in cocked position. The forward portion of the striker is formed with a cocking cam 60 co-operating with a cocking cam face El at the rear of the breech block. As will be understood by comparison of the position of the parts in Fig. 2 with those of Fig. l, the striker is cammed rearwardly, during opening of the breech parts, by the interaction of said cam faces G0 and 6I.

The sear 59 is guided for vertical movement in the link "I, by suitable guides, including the depending portion 65 below referred to, and in part by the stud 62 extending through the sear and removably held in place by a lock plate 63. low the stud 62 is a spring 54 housed in a hollow plunger or barrel portion 65 depending from the sear 59 and movably positioned in the link, said plunger and the sear itself thus being urged downwardly by said spring against one arm of a bellcrank lever 66 pivoted in the link 1. Said lever is prevented from rearward or counter-clockwise movement by the adjacent surface 66a of the link 1. Forward movement of the lower arm of the bell-crank lever 66 is adapted to elevate the scar 59 and release the striker, to fire the gun.

Any, suitable form of trigger mechanism may be provided for actuating the sear 59 and the lever 66, such, for example, as in my copending applications Serial Nos. 419,318 and 576,666, now Patents Nos. 1,907,164 and 1,907,163 dated May 2, 1933. Automatic cartridge supplying means is also contemplated, which likewise may be, for example, such as that of said previous applications.

aosaeav The action of the gun is as follows:-

On ignition of the charge, the recoil mass, consisting of the barrel I, the receiver 2, the toggle mechanism and actuator, commence to move rearwardly, as the bullet starts forward, with a velocity dependent on their combined weights. During the first part of this movement (represented by the gap of some of an inch shown at 6l between the face 68 of the actuator and shoulders d1 on the abutment 5) no event occurs except the pushing in of the plungers 38. It will be understood that the pressure locking surfaces, including the shoulders 29, 38 intermediate the/ crank and receiver, are so held together by the high chamber gas pressure that no movement to unlock can occur during the movement of the plungers 38. However, by the time the shoulders lil of the abutment 5 have been contacted by the corresponding surfaces of the actuator face 68 sumcient time has elapsed to allow the bullet to leave the barrel and the chamber pressure to fall substantially to zero. The aforesaid recoiling mass, except the actuator, is still at this time free to move an additional 12 of an inch or thereabouts and the pressure now existing between. the abutment 5 and the spring plungers of the arrested actuator causes the link 32 (as its pivotal connection at 3i to the crank continues to recoil) to break the toggle upwards and tofseparate the pressure locking shoulders 29. As the explosion pressure resisting surfaces between the breech block, link and crank at 2l, 28, and 29 are not now held frictionally the crank is free to swing upwardly and open the breech. The aforesaid 7,35 of an inch of recoil movement between the actuator and the pivot Si of the link 32 thus starts the crank through its opening arc of movement and the completion of this movement ls in part brought about by the momentum of the mass of metal in the crank and the link assisted by the reaction of the springs o the plungers 38, the faces 41 and BB moving apart as the breech opening is thus completed. The limit of the swing of the crank is determined by a shoulder 69 of the receiver 2, the crank being cushioned by the spring buffer 25 on the crank contacting with the corner lll Y of the said receiver shoulder B9. The empty shell is extracted from the chamber by the extractor i5 on the breech block. When the breech block 5 has moved rearwardly the length of the empty cartridge case the latter is expelled from the receiver by the spring controlled ejector pin 53 also carried in the breech block. The crank 8, the link 'l and the breech block 6, by a return or straightening movement, due to the actuator spring 36, now' feed a live cartridge into the chamber, and the gun can be fired again by the trigger mechanism (not shown) which connects with the bell crank lever 66. This lever 66 pushes the sear 59 upwardly, releasing the striker 55. The striker 58 hits the firing pin 52 and the primer is exploded. 'Ihe striker 56 is rectilineally guided along the link l which carries it and is cocked as the toggle breaks by the cooking cam face 6| formed on the breech block and acting as the toggle is straightened again as a safety cam preventing premature firing.

Easy separation of the locking surfaces 29 for opening the breech when the chamber gas pressure has been dissipated is provided for by the previously mentioned suitable degree of looseness of fit of the fulcrum pin 22 with respect to the crank. This looseness while not affecting the service of the pin as a pivotal point for the crank swing allows that intimate contact of the locking surfaces at 29 which is brought about irst by the action spring 36 and then intensified by the chamber gas pressure and which causes the breech to be securely locked automatically by the chamber gas pressure itself until the latter has fal'en at least substantially to zero.

It will be observed that none of the pivots of the breech mechanism are called upon to resist the stresses set up bythe discharge of the firearm, these stresses being taken by the faces at 27, 28, 29, and 30 so that apart from having the element of safety which is introduced by the gaspressure locking action above referred to, the mechanism shown has the advantage that it may be made of comparatively light compact members. Main the mechanism shown operates to produce a. long opening movement of the breech block from but a comparatively short recoi`'n the particular instance considered a total recoil of but some 1/4 inch serves to effect adequate breech opening for feeding an ordinary 0.30 calibre rifle cartridge (probably the longest military rifle cartridge made) into the chamber.

My invention is not limited to the particular embodiment thereof herein shown and described, its scope being pointed out in the following claims.

I claim:

1. An automatic gun comprisingin combination, a barrel and receiver mounted to have recoil and counter-recoil or return movement relative to a stock, and recoil-operated breech closure mechanism including a block movable rectilineally in the receiver, a link rearwardly of the block and plvoted thereto, and a crank pivotally mounted on a crank pin in the receiver, rearwardly of the link and having pivotal connection with the latter, said block, link and crank forming substantially a unitary mass in their breech closing position and having a toggle-like opening and closing action, there being relatively large area abutments on the receiver and cooperating large area surfaces on the crank, the block and the link also having rearwardly of their interconnecting pivot cooperating pressure-transmitting lockingr surfaces of substantial area, and said crank pin having throughout the width of the crank a portion of less diameter than that of the pin receiving formations of the crank to afford an operative clearance for the crank pin relative to the crank, main spring return means for the receiver and breech closure mechanism, and other spring-loaded means for assisting in opening said breech closure mechanism, said large area abutments and surfaces on the block, link, crank and the receiver in cooperation with said crank pin structure being effective to transmit the breech pressure to the receiver independently of said crank pin and to insure intimate contact of said pressure-transmitting and locking sur- ,faces such that the breech closure mechanism is breech mechanism including' a reciprocatory necting the crank and actuator, and one or more spring-pressed plungers carried by the actuator i and :engaging a xed abutment thereby to energize the actuator during recoilr movement of lthe parts, to assist in the breech-opening effort.

4. In a gun of the class described, a receiver,

f breech mechanismy rincluding ra reciprocatory block, a link pivotedr at the rear of the block, and f a crank 'pivoted in the receiverr andfhaving pivoa crank pivoted in the receiver and havirg pivotal connection withy said link, an actuator slidably mounted on the receiver, an actuator linky connecting the crank and actuator, and one or morey spring-,pressed plungers carried bythe actuator and engag'ing'a xedy abutment thereby to energize the actuator during recoil movement rofthel parts, to assist inthe breech-opening efg f of lsaid spring,y and releasable locking means for fort, said actuator being provided with a rmain ,return spring housed in a portion thereof and bearing between afwall of theactuator andar portion of the receiverto assist in the counterf recoil or return movement of the receiver and barrel and' to eiiect'closure ofthe breech mechanism. f

5. In a gun of the class described, a receiver, breech vmechanism including ra reciprocatory block, a link pivoted at the rear vof the block, and f a crank pivoted in the receiver and having/pivrotal connection with saidr link,r an actuator slidably mounted on the receiver,v anA actuator link l connecting the crank and actuator, and one or more spring-pressedplungers carried by the actuator and engaging' a fixed abutment' thereby toA energize the actuator during recoii movement ci' the parts, tov assist in the breech-opening effort, said actuator'being provided vwith a rmain return. spring housed in a portion thereof and bearing between a wall of the actuator and a portion of the receiver to assist in the counter-recoil or return movement of the receiver and barrel and to effect closure of the breech mechanism, and an auxiliary return spring acting substantially in parallelism with said main spring, bearing between the receiver and a xed abutment on the stock.

6. In a gun of the class described, a receiver, breech mechanism including a rectilineal'ly reciprocatory block, a link pivoted at the rear of the block, and a crank pivoted in the receiver and having pivotal connection with said link, a ring pin carried by the block, and a striker and a sear therefor carried by said pivoted link, the block and the striker being provided with cooperating cam surfaces for cooking the striker during opening of the breech mechanism.

7. In a gun of the class described, a receiver, breech mechanism including a reciprocatory block, a link pivoted at the rear of the block, and a crank pivoted in the receiver and having pivotal connection with said link, a movable extractor at the fore end of the block, said pivotal connection of the block and the link comprising an annularly recessed fulcrum pin interconnecting said parts, a movable pin in the block engageable in said annular recess of the fulcrum pin to secure the latter, and a spring acting in one direction to engage said movable pin in said recess and oppositely to tension the extractor.

8. In a gun of the class described, a receiver, breech mechanism including a rectilineally reciprocatory block. a link pivoted at the rear of f the block, anda crank pivoted. in the receiver and having pivotal connection with said link, a firing pin carried by the block, and a striker and sear ymechanism therefor ,carried by said pivoted link,

said' sear mechanism comprising a sear guided for movement transversely of and upon the link, spring means rurging the sear toward strikerengaging position, and a pivoted leverengaging the sear and operable by trigger mechanism to f release the Sear from the striker.

9. In a gun of -the class described, a receiver,

Abreech mechanism including a reciprocatory block,"a link pivoted at the rear lof, the block, and

tal connection with said link, a slidable Aplunger housed in the crank and'having an outer portion adapted to engage a solid part 'of the receiver y,

to limit and cushion the crank in its opening swing, a coil springin the crank bearing at one end against said plunger, va rremovable memberin the crank providing a seat for the opposite end said member.

lli. A gun in accordance with claim 3 Wheref inthey crank .is mounted on a crank pin having throughout the Width of the crank afportionof such distinctly and designedly' less diameter than that of the pin receiving formation of the crank 'as to aord anfoperative clearance for they cranky pin relative to the crank.

l1. An automaticor semi-,automatic gun of the recoil-operative breech mechanism including a reciprocatory block, a crank pivoted in the receiver, aflinki between andvpivotally connected with the block and the crank, there being cooperatingr relatively large-,area abutments on the class described, said gun having la. receiver' and a l l receiver and on the'crank, and said crank having a crank pin held in the receiver, main spring rekturn means fork the receiver and breech mechanism, and other spring-loaded means for assistingl in opening said breech mechanism, said crank pin having a distinct and designed clearance with respect to the crank whereby the breech pressure received by the crank is transmitted directly by the latter to the receiver through said abutments independently of said crank pin, the breech closure mechanism during the recoil being released for automatic opening only upon the gas pressure in the barrel falling substantially to zero.

12. In a gun of the class described, a receiver, breech mechanism including a reciprocatory block, a link pivoted at the rear of the block, and a crank pivoted in the receiver and having pivotal connection with said link, an actuator slidably mounted on the receiver, an actuator link connecting the crank and actuator, and actuator spring means operatively interposed between said actuator and a non-recoiling part, the construction and arrangement being such that said actuator and its spring means are energized by and during the initial recoil, and thereby are conditioned to initiate and assist in opening of the breech during the remaining recoil, when the gas pressure in the barrel has materially fallen.

13. In an automatic shoulder riiie operated by recoil, a slidable barrel and receiver, toggle-like breech mechanism including a block slidable on the receiver, a crank having pivotal connection with the receiver, and a link pivotally connecting initial recoil of the receiver to assist 'in opening the breech mechanism during the continued recoil.

14. In an automatic shoulder rifle operated by recoil, a slidable barrel and receiver, toggle-like breech mechanism including a klock slidable on the receiver, a crank having pivoted connection with the receiver, and a link pivotally connecting the block and crank, an actuator link pivoted to said crank, an actuator slidably positioned on the receiver and pivotally engaged with said acl tuator link, and spring means for moving the actuator to initiate opening of the breech mechanism, said spring means arranged for operative loading during recoil of the receiver.

15. In an automatic shoulder rifle operated by recoil, a slidable barrel and receiver, toggle-like breech mechanism including` a block slidable on the receiver, a crank having pivotal connection with the receiver, and a link pivotally connecting the block and crank, an actuator link pivoted to said crank, an actuator slidably positioned on the receiver and pivotally engaged with said actuator link, and spring means for moving the actuator to initiate opening of the breech mechanism, recoil of the receiver and closed breech mechanism serving to load said spring means for said opening action thereof upon substantial reduction of the gas pressure in the barrel.

16. In an automatic shoulder rie operated by recoil, a slidable barrel and receiver, toggle-like breech mechanism including a block slidable on the receiver, a crank having pivotal connection with the receiver, and a link pivotally connecting the block and crank, an actuator link pivoted to said crank, an actuator slidably positioned on the receiver and pivotally engaged with said actuator link, said actuator adapted to travel with the receiver during initial recoil of the latter, and actuator spring means arranged to be loaded during said initial recoil, said actuator being moved by said spring means reversely relative to the receiver during further recoil of the latter thereby to break open said toggle-like breech mechanism.

17. In an automatic shoulder rifle operated by recoil, a slidable barrel and receiver, togglelike breech mechanism including a block slidable on the receiver, a crank having pivotal connection with the receiver, and a link pivotally connecting the block and crank, locking formations of substantial area on said breech mechanism and corresponding abutment formations on the receiver, main spring return means for the receiver and breech mechanism, and other springloaded means for breaking open said breech mechanism, said barrel and receiver having a total recoil materially less than the length of the cartridge for the rie, the pivotal connection of said crank and receiver comprising a pivot pin having a clearance formation adequate to provide for relative bodily movement between said parts, said breech mechanism remaining closed during a substantial initial portion of said total recoil of the barrel and receiver, and said crank pivot connection providing for intimate pressure-locked contact of said locking and abutment formations and for their rapid release by said spring-loaded means on dropping of the gas pressure, whereby complete opening of the breech mechanism is effected during the remainder of said short total recoil.

breech mechanism including a block slidable on the receiver, a crank having pivotal connection with the receiver, and a link pivotally connecting the block and crank, an actuator link pivoted to said crank, an actuator slidably positioned on the receiver and pivotally engaged with said actuator link, spring means for said actuator, said actuator and its spring means being energized by initial recoil of the receiver to assist in opening the breech mechanism during the continued recoil, the total recoil of the barrel and receiver being limited in length to a minor fraction of the length of the riiie cartridge, and said pivotal connection of the crank and receiver providing for relative bodily movement between Said parts, whereby the breech opening action may be delayed, during said initial recoil, yet is completed during the full recoil despite the short total length of the latter.

19. In an automatic shoulder riiie operated by recoil, a recoiling receiver, breech mechanism in the receiver including a reciprocating block, a crank having pivotal connection with the receiver and a link pivotally connecting the block and crank, spring means for assisting the initial opening movement of the bre'ech mechanism, means whereby said spring means is energized during the initial recoil and becomes operative during subsequent recoil, including a slidable part on the ireceiver and a link pivotally connecting it to the crank, and other spring means for returning the receiver and breech mechanism to closed position.

20. In an automatic shoulder rifle operated by recoil, a recoiling receiver, breech mechanism in the receiver including a reciprocating block, a crank having pivotal connection with the receiver and a link pivotally connecting the block and crank, spring means for assisting the initial opening movement of the breech mechanism, means whereby said spring means is energized during the initial recoil and becomes operative during subsequent recoil, including a slidable part on the'receiver and a link pivotally connecting it to the crank, and other spring means for returning the receiver and breech mechanism to closed position, there being abutment locking formations between the breech mechanism and the receiver, and the pivotal connection between the crank and receiver being arranged to afford relative bodily movement between said parts, for the purposes of intimate pressure-closed contact of said locking formations and of rapid release thereof in opening the breech mechanism.

21. In an automatic shoulder riiie operated by recoil, a recoiling receiver, breech mechanism in the receiver including a reciprocating block, a crank having pivotalconnection with the receiver and a link pivotally connecting the block and crank, spring means for returning the receiver and for closing the breech mechanism, and other means, carried by the crank, for cushioning its opening swing, said means comprising a buffer element housed in the crank and having an outer face adapted to make angular sliding contact with a part which is iixed with respect to the receiver, and spring means urging said buffer element outwardly.

JOSEPH C. WHITE. 

